1. Field of the Invention
The invention relates chiefly to a controlled valve (defined herein as a valve that operates under a control applied to it) with a clack valve (defined herein as a valve that opens and shuts automatically under pressure applied to it) and a clack valve including a controlled valve as well as an aircraft having a controlled valve of this type.
2. Description of the Prior Art
Firstly, there are prior art controlled valves which make it possible, on command or actuation, to let through a desired flow rate of a fluid between, for example, two chambers within which different pressures prevail. The prior art type controlled valves enable the regulation of flow rates or pressures. To enable stable regulation, the controlled valves are designed to work in a determined range of flow rates. Thus, it is not possible, on command, for example if there is trouble, to balance the pressures by fast and complete opening of the controlled valve. Furthermore, the prior art type controlled valves act only upon external actuation. Thus, the malfunctioning of the external actuating device makes the controlled valve completely ineffective.
Secondly, there are prior art clack valves, designed to open if the pressure difference between their two faces goes beyond a pre-determined threshold. Clack valves can be used to make reliable, autonomous safety systems. The instantaneous opening of the clack valve enables fast balancing of pressures on either side of said clack valve. However, it is not possible to control the flow passing through an open clack valve.
Now, it turns out that the fact of having a clack valve or a controlled valve on a partition wall between, for example, two chambers or between a chamber and the exterior, raises major problems. Firstly, there should be the space needed for the controlled valve and the clack valve. This is not always the case, notably if the controlled valves and clack valves have to be placed, for example, on a piping system that connects tubes of chemical reactors or the points of, for example, a petroleum distillation tower.
Secondly, the fact of making an opening, needed for the controlled valve and the clack valve to pass through, embrittles the wall. This embrittlement could be partially compensated for by a structure which is, for example, metallic, positioned around the controlled valve and the clack valve. However, this metallic structure is costly and heavy. The additional weight has particularly serious implications in the context of aircraft manufacturing.